Ok, I tried that. It definitely improves performance when using a lot threads (15+) but decreases the performance considerably when using only two thread (from 60s down to 100s).
------------------------------------------------------------------ SELECT_COUNT: 1,000,000 THREAD_COUNT: 2 Testing with one connection (ReadWrite) and filled table... Elapsed: 58.9 s (33,938.7 stmt/sec) Testing with multiple connections (ReadWrite) and filled table... Elapsed: 102.7 s (19,482.7 stmt/sec) ------------------------------------------------------------------ SELECT_COUNT: 133,333 THREAD_COUNT: 15 Testing with one connection (ReadWrite) and filled table... Elapsed: 12.3 s (162,647.6 stmt/sec) Testing with multiple connections (ReadWrite) and filled table... Elapsed: 12.7 s (157,324.1 stmt/sec) ------------------------------------------------------------------ SELECT_COUNT: 20,000 THREAD_COUNT: 100 Testing with one connection (ReadWrite) and filled table... Elapsed: 11.8 s (169,204.7 stmt/sec) Testing with multiple connections (ReadWrite) and filled table... Elapsed: 15.0 s (133,612.1 stmt/sec) - Sebastian On Fri, Sep 21, 2012 at 7:45 PM, Keith Medcalf <kmedc...@dessus.com> wrote: > > On Friday, 21 September, 2012, @10:53, Sebastian Krysmanski said: > > > I wish it were like you said. However, in my understanding multiple > > connections to the same database are realized by file system locks. So > > switching from serialized to multi-threading mode doesn't make much > > difference because the main slow down are the file system locks. > > Can you try passing the SQLITE_OPEN_SHAREDCACHE and SQLITE_OPEN_NOMUTEX to > the connection per thread and see how that behaves. You get the same > advantage of reducing I/O and memory management by using a single > page-cache, yet you now no longer have serialization (or mutexes to enforce > serialization) in the library call path. If the serialization/mutex code > is causing any significant performance effect, this should demonstrate it > clearly. > > --- > () ascii ribbon campaign against html e-mail > /\ www.asciiribbon.org > > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
